GMC 1996 Sonoma Owner's Manual page 70

4LO:
This setting also engages your
front
axle
to
give
you extra traction and provides extra gear reduction.
You may never need 4LO. It sends the maximum
power
to all four wheels. You might choose 4LO if you were
driving off-road in sand, mud, or deep snow and
climbing or descending steep hills.
You can shift from 2HI to 4HI or from 4H1 to 2HI while
the vehicle is moving. Do not press the transfer case
shift lever button when shifting from 2HI to 4HI or from
4HI to 2HI. Your front axle will engage faster if you
take your foot off of the accelerator for a few seconds
after you shift.
To shift your transfer case into N SET PARK BRAKE:
1. Stop the vehicle and shift your transmission into
NEUTRAL (N).
2 . Set the parking brake. Your vehicle can roll unless
the brakes are applied.
3. Pull the transfer case shift lever into N SET
PARK BRAKE.
To shift into or out of 4LO:
I. The vehicle must be moving less than 3 mph
(4.8 km) with the transmission in NEUTRAL (N)
for an automatic transmission. For a manual
transmission, the clutch pedal must be engaged. The
preferred method for shifting into 4LO is to have
your vehicle moving 1 to 2 mph (1.6 to 3.2 k d h ) .
2. Press the transfer case shift button and shift in one
continuous motion.
Don't pause in N SET PARK BRAKE as you shift into
or out of 4L0, or your gears could clash.
Remember that driving in 4HI or 4LO may reduce
fuel economy. Also, driving in four-wheel drive on
dry pavement could cause your tires to wear faster and
make your transfer case harder to shift and reduce
powertrain longevity.
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